Characterizing phosphorus lability pools through sequential fractionation of muck soils in Ontario

Session: Poster session

Aidan De Sena, McGill University, [email protected]

Abstract

A thorough understanding of the soil agricultural phosphorus (P) cycle and its various lability pools is necessary in order to prevent P pollution from arable fields, and subsequently eutrophication. Though there have been robust studies on the distribution of P in these pools, many occur on mineral soils, resulting in a gap of knowledge on P fractionation in muck soils. This study aimed to determine the agricultural P pools of three intensively cultivated Histosol farms in the Holland Marsh, Ontario over three agricultural periods. Through sequential fractionation of the topsoil (0-20cm), both inorganic and organic P concentrations were classified as either available, moderately labile, iron/aluminum-bound non-labile, or calcium-bound non-labile. Results showed overall high concentrations of inorganic P in the non-labile pools of the topsoil for the three fields, especially the calcium-bound non-labile fraction (545–1,633mg P/kg), representing 41–74% proportion of the total P. Though organic phosphorus concentrations were higher than in mineral soils, ranging between 0.00–221mg P/kg among the various pools, their proportions of total P were minimal (6–22%). Despite the differences between inorganic and organic soils, the results of this study generally agree with the model for mineral soils, where over time P becomes increasingly recalcitrant and non-labile.

1. Keyword
phosphorus

2. Keyword
nutrients

3. Keyword
Lake Simcoe

4. Additional Keyword
phosphorus lability pools

5. Additional Keyword
sequential fractionation

6. Additional Keyword
muck soils